The present specification relates generally to lithium batteries and, more specifically, to lithium batteries including an artificial solid electrolyte interphase membrane to enhance cycle life and maximize usable energy density.
Lithium-ion batteries are widely used in devices such as smart phones, laptops, and vehicles. Lithium metal is an ideal anode material for rechargeable batteries because it has a high theoretical specific capacity (3860 mAh/g), a low density (0.59 g/cm3), and a low negative electrochemical potential (−3.04 V vs. the standard hydrogen electrode). The use of a lithium metal-based battery has the potential for significantly higher energy density and power density over the use of other electrochemical batteries. Estimations suggest that a lithium battery based on a lithium metal anode can be up to ten times more energy dense than current lithium ion batteries.
However, a problem with the use of lithium metal anodes is the formation of microscopic fibers of lithium, called dendrites, over the course of several battery charge/discharge cycles. The formation and growth of dendrites on the anode during charge/discharge cycles cause low usable lithium energy or short-circuiting in a rechargeable battery system. Short-circuiting in particular can cause the battery to rapidly overheat or to start a fire.
Uncontrolled lithium dendrite growth and limited Coulombic efficiency (CE) during lithium deposition and depletion of a bulk lithium anode are the factors that lead to low cycle life. Furthermore, the rate of dendrite growth is amplified when the cell is cycled at high charge-discharge current density in a bulk lithium anode. Increasing anode surface area would reduce the effective charge/discharge current. Although low CE can be partially compensated for by using an excess amount of lithium to provide increased surface area at the expense of lower usable lithium energy, fire and other hazards associated with dendrite growth have limited the development of rechargeable lithium metal batteries. Accordingly, ongoing needs exist for technologies that both prevent dendrite growth and maximize the usable lithium energy in lithium batteries.